Annelid
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| Annelids Fossil range: Cambrian - Recent |
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 Glycera sp.
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Class Polychaeta (paraphyletic?) |
Annelids are a phylum of Invertebrates. Sometimes they are called by their Latin name Annelida. They include the segmented worms, with about 15.0000 known species. Well known species are earthworms and leeches. Annelids can be found in most wet environments. Some of these species are parasites, or mutualistic. This means they live together with (or inside) another organism. In the case of a mutualistic relationship, this is beneficial to both organisms. Their size varies from under a millimetre to about 3 metres. The largest known species is the seep tube worm (Lamellibrachia lymnesi) related to the giant tube worm.
Annelids are made of one or more body segments. Each segment has one or more rings. These rings are called annuli (singular: annulus). Depending on the species, annelids can reproduce both sexually and asexually.
